There are a couple official Disney table trees and there are several others available at most Christmas shops if you don’t need Disney. They’re little, but they are symbolic.
I’ve started putting lights on the room’s window along with several Disney characters in Christmas garb.
I’ve seen others put all kinds of decorations up.
Just keep in mind that whatever you do, it must be non destructive. This means suction cups and those 3M Command brand hangers.
I’m not sure how you want to handle actual Christmas gifts, other than to remind you that if you ship it down, you’ll have to ship it back. Unless you’re driving and your car has room.
Something you might consider (I don’t have kids, so I might not know what I’m talking about), pick up some stuff in WDW, pay to have it wrapped, and then have it sent to your resort for pick up on the afternoon of 12/24.
This way you’ll have some gifts and you can tell them that Santa left the big presents for them when you get home.